What are "Flow Regulations"?
 

It's amazing how fast you go from feeling like an well informed enthusiast, to a complete waste of volume, when you have a conversation with someone actually in the industry.:ouch:

In order to help me claw back shreds of whatever is left of my self respect, could someone help in answering a few questions for me? The first is this:

What are flow regulations (commonly refered to as "regs")? In particular, at what point are they put in place, how do they help reduce jams. Are they for arrivals or departures? When do you know when to take them away? What exactly is being regulated (what phase of the flight)? In essence, educate me. I'm looking particularly at the EGLL situation, but general info is helpful too!

Thanks all you wonderful people.

'hotep.

A very complicated subject which I am not really qualified to write about, being a mere tower controller. However, as a good start Google Eurocontrol CFMU and the basics are explained. You will have to wade through a lot of acronyms though!

Have a look at Wikipedia: Air Traffic Flow Management

Edited to add - also check the UK AIP ATFM. It's quite dry though!

Awesome repositories of information, thanks guys.

Don't worry about the acronyms and dry texts, I'm used to it by now. It is a really complex issue but ideally I should to get to grips with it, as part of my job is to report on the causes of delays.

:ok:

If you're not already aware, lots of info at the CFMU NOP.

Basically the amount of aircraft that can pass over a certain point during a set period of time. This is laid down by either the country of overflight or maybe nowadays by the CFMU. These regulations can change at any time due to the airspace complexity and density of traffic. There are also planning stages for the regulations and reactive stages to implement them on a daily basis. Now the single european sky is slowly being implemented and other complicated issues around europe they will constantly change. Hope this helps its a while since I researched this for my own advancement.

Rgds.

PS Also more complicated than I have explained.

"Basically the amount of aircraft that can pass over a certain point during a set period of time. This is laid down by either the country of overflight or maybe nowadays by the CFMU. These regulations can change at any time due to the airspace complexity and density of traffic. There are also planning stages for the regulations and reactive stages to implement them on a daily basis. Now the single european sky is slowly being implemented and other complicated issues around europe they will constantly change. Hope this helps its a while since I researched this for my own advancement."

:=It's NUMBER of aircraft not amount.
Have a nice day:)

A simple way to think of it is that each route is a 'pipe' and only a certain number of a/c can be in it at any time and must be separated by a certain distance.

When the French go on their regular strikes and try to screw things up, they introduce 'flow control' which increases the distance allowed between each a/c, thus reducing the carrying capacity of the 'pipe'.

Same thing. Just measure it in zeptomoles. :)

Unfortunately there is another side to the flow management restrictions. As well as the CFMU generated slot times which are there for all to see with each delay having a code attributed to define its cause, there are London ACC restrictions in the form of MDI's/ADI's (minimum departure interval or average departure interval. For the sake of this discussion we can treat them as the same thing).
They are generally put on for short term issues such as weather in a sector or perceived bunching of traffic. A restriction will be placed on an airfield and a particular route imposing a minimum departure interval. For instance a CPT departure may normally be a 2 minute IFR route separation but due to weather or a potential over delivery further down the line, the London flow management unit will impose a further restriction. Often this just takes the form of a request not to take the piss but can also be a specified minimum interval such as 1 every 3 minutes. When sectors are really going under with weather I have seen 1 every 10 minutes put on with immediate effect. That can really spoil your day as a departures controller!
These MDI delays are not recorded in the official delay stats like CFMU restriction and are not transparent to the airlines. They are simply applied at the sharp end to the best of our ability.
Don't worry though, technology is here to save us. CDM and the magic TSAT machine will, by a mix of black magic and blind guessing, generate a target start approval time for each aircraft. This is made possible because all operators are so amazing at updating their EOBT to reflect their actual state of readiness.:ugh: From this the machine will take account of a myriad of other factors, multiply the result by the square root of Pi and tell us when you should start for an unimpeded taxi to the hold where you will arrive, no doubt fully ready with final figures in hand and be promptly cleared for take off.............:D

Thanks guys, as ever, a great response.

:ok:

And I understand what you mean about the EOBTs. Unless everyone updates the records accurately, the whole system fails. I'm analysing delay codes, which is known for a fact to be mostly garbage, on the understanding that hopefully, airlines and handlers will start being more honest and actually give a damn. :}

Hope springs eternal. Forgive me if I don't hold my breath though. What hope do we have of getting crews to be realistic with their company about when they will be ready when they still habitually call ATC "ready" with all the bloody doors open and bags still going on. It still amazes me how often the conversation goes "ABC123 how long until you are ready? ABC123 we will be 10 minutes. ATC, OK then you are going to miss your CTOT I'll get you a new one. ABC123 is fully ready."
Must think we're idiots.